Tiny Golem 2

The golem spell was advanced-level but didn't require much time to gather mana for, especially when Damian filled the surroundings with his own mana, allowing it to accumulate faster. He needed the slab because he couldn't use mana threads inside the invisible box that wasn't even cast by him. To ensure the best possible result, he set the spell's mana requirements to their absolute maximum. The slab was a one time use thing anyway. 

Like many basic and advanced spells, the golem spell's effectiveness depended on the amount of mana supplied. While most spells had fixed parameters, some—such as this one—featured a customizable mana section. Damian could make any spell mana dependent if he wanted to, with adding that section in them, but not many spells would show the difference. More mana equal to better effect was only possible if the spell was conjuring type mostly.